CHLOROPHYLL-COKPUSCLES AND AMYLOID DEPOSITS. 241 



that they have originated by a process of cleavage of an 

 crio-inal layer of green substance which invested the particle 

 of protoplasm. Evidence of the cleaving of the chlorophyll- 

 corpuscles, so as to form two corpuscles from one, is given in 

 the accompanying drawings (fig. 9 c). 



I am not acquainted with any chlorophyll bodies of plants 

 which assume the form of concavo-convex discs as do those 

 of Spongilla. At the same time there is nothing incon- 

 sistent with what is known of chlorophyll bodies in this form, 

 whilst in their simple negative characters the green cor- 

 puscles of Spongilla are like the chlorophyll bodies of 

 higher plants. They are quite unlike any known forms of 

 unicellular Algae. 



Amyloid substance in Spongilla. — Neither before treatment 

 with alcohol nor after it did the addition of iodine solution 

 to the sponge-cells reveal any substance within the cor- 

 puscles, which by its blue or violet coloration could suggest 

 the presence of starch. 



I, however, obtained in both green and colourless speci- 

 mens of Spongilla treated in this way with iodine solution 

 abundant evidence of the presence in other regions of the 

 sponge-cell of an amyloid substance. My observations 

 were made on specimens taken late in the year (October), 

 and I am inclined to believe, from my recollection of former 

 experiments, that the amyloid substance is not so abundant 

 in the early part of the year as in autumn. 



The amyloid substance occurred in two forms — (1) as a 

 homogeneous substance occupying very large vacuoles — 

 usually only one — in the protoplasm of the sponge-cell (PL 

 XX, figs. 3, 4), and (2) as fine spherical granules, which 

 were accumulated on the surface of some of the sponge- 

 cells, and embedded in the superficial layer of the protoplasm 

 (PI. XX, figs. 4, 5, 8). 



The amyloid vacuoles of Spongilla and of other sponges 

 were discovered and described by Keller (' Zeitschr. fiir 

 wiss. Zoologie,' vol. xxx, p. 572). Keller points out that 

 the vacuoles contain a fluid which stains deep blue or violet 

 when iodine solution is added (in my observations I obtained 

 only violet staining), and that the substauce so coloured is 

 insoluble, either in ordinary or absolute alcohol or in cold 

 ■water, whilst potash solution decolorises the stained vacuole 

 and causes the cell to swell up. 



Keller's observations undoubtedly prove that we have in 

 these vacuoles a starch-like substance in solution, but it is 

 by no means to be concluded that this substance is identical 

 with vegetable starch. 



VOL. XXII. NEW SER. Q 



